【電験三種】理論 令和7年上期 問15　Δ 結線と 𝐘 結線の関係

This question asks for the line and phase currents flowing in a three-phase balanced circuit, and is a question that can easily result in a large difference in scores depending on your strengths and weaknesses. This video carefully explains the relationship between phase currents and line currents, and explains a solution with as little calculation required as possible, so please watch until the end. The key to solving this problem is the relationship between the Δ connection and the 𝐘 connection. 0:00 Intro & Profile and New Book Introduction 01:03 Question 01:46 Quick Explanation 1. ∆−𝐘 Transformation and 𝐘−𝐘 Transformation 04:06 Quick Explanation 2. Relationship between Phase Voltage and Line Voltage in 𝐘 Connection 05:47 Quick Explanation 3. Relationship between Phase Current and Line Current in 𝚫 Connection 07:21 Quick Explanation 4. Notation of Complex Numbers in the Complex Plane 08:39 Answer and Explanation (a) 11:15 Answers and Explanations (b) 11:54 Summary --------------------------------------- ★Explanation from the Denken-ou website (Electrical Engineering Examination, Grade 3 Theory, 2025, First Half, Question 15) https://denken-ou.com/rironr7-1-15/ ☆Reprint of Question 6 from the 2012 Electrical Engineering Examination, Grade 3 Theory https://denken-ou.com/rironh24-16/ ★[E-Book Version of Denken-ou] Electrical Engineering Examination, Grade 3, 4 Subjects Second half of 2020 edition Year order https://denken-ou-tanaoroshi.com/item... Sort by field https://denken-ou-tanaoroshi.com/item... 3 types of theory by subject Yearly order https://denken-ou-tanaoroshi.com/item... ea71f3227b5b5c14 By subject: https://denken-ou-tanaoroshi.com/item... ★Download the trial version [E-book version of Denken-O] https://denken-ou-tanaoroshi.com/item... ★Click here for the paperback version Available on Amazon [E-book version of Denken-O] Electrical Engineering Examination, Grade 3, 4 Subjects, Second Half of 2025 https://amzn.to/4nRHKru ★New Reference Book from a Collaboration between Electrical Engineering Academia and Denken-oh [Thermal Power Generation] Electrical Engineering Warrior Textbook - Denken Soldiers Spellbook - https://denkenia-archives.stores.jp/i... [DC Circuits] Electrical Engineering Warrior Textbook - Denken Soldiers Spellbook - https://denkenia-archives.stores.jp/i... --------------------------------------- #Electrical Engineering Examination, Grade 3 #Theory #Explanation of Past Questions #Denken-oh #First Half of 2025 #Question 15 #Electrical Circuits #Phase Current and Line Current